1. Field of the Invention
The present invention relates generally to chairs with flexible backrests. More particularly, the present invention relates to a chair having a back support structure that is resiliently hingedly coupled to the seat and supporting structure.
2. Related Art
Reclining chairs are generally considered more comfortable than non-reclining chairs. Of the variety of reclining chairs, some comprise a chair with a fixed seat and a backrest that is configured to flex or recline backward relative to the seat. There are a variety of types of chairs with flexible or reclining backrests. Some of these involve very complicated reclining mechanisms. Some involve flexible members that bend along their length, while others include relatively rigid frame components that are hingedly coupled together in various locations.
Unfortunately, many of the reclining mechanisms that have been developed are not suitable to simple, relatively low-cost chairs, such as stackable banquet or meeting hall chairs. A bulky reclining mechanism is not suitable for stackable chairs, and an expensive mechanism is not desirable for locations such as hotels and the like, which require large numbers of chairs for banquets, conferences, etc.
Another problem with some simple reclining back chairs is the location where the chair reclines or bends. To be comfortable, a reclining chair should bend in a location that corresponds as closely as possible to the motion of the human body. Some flex-back chairs bend in places that actually make reclining less comfortable, and others merely tip back, without actually reclining. Both of these motions do not adequately address the structure and motion of the human body.
Additionally, some reclining mechanisms, particularly the more simple ones, present pinch points where a user""s; fingers or other items can get caught. While there are various methods that have been devised for reducing, or hiding pinch points, many prior solutions have not adequately addressed the problem in an effective and inexpensive manner.
The present invention advantageously provides a chair having a hollow tubular seat frame, a hollow tubular backrest frame pivotally connected to the seat frame at fixed pivot points, a limit stop, affixed to the backrest frame and the seat frame adjacent to the pivot points, and a substantially solid elongate spring element, extending from within the backrest frame into the seat frame. The limit stop is configured to limit a degree of rotation of the backrest frame relative to the seat frame between an upright position and a maximum backwardly rotated position, and the spring element is configured to bias the backrest frame in the upright position, and to resiliently resist backward rotation of the backrest frame.
In accordance with a more detailed aspect of the present invention, in one embodiment the spring element includes a curved lower surface, providing an effective fulcrum point which moves rearwardly as the backrest frame is rotated backwardly, thereby increasing the effective flexural resistance of the spring element during backward rotation.
Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.